P018A: Fuel Pressure Sensor B Circuit

What does P018A mean?

Fuel pressure sensor B is a second fuel pressure sensor; which one is up to the manufacturer. On GM it is the low-pressure sensor in the supply line of direct-injection engines (0–743 kPa), read by the engine module or the fuel pump control module; on Ford engines with dual injection it is the sensor on the port-injection rail (0.5–4.5 V for about 0–70 psi). Sensor A is the high-pressure rail sensor (P0190–P0194). P018A is the general circuit fault for when a manufacturer does not distinguish low from high. GM and Ford, whose sensor B functions are documented, use P018C/P018D instead, so no manufacturer document using exactly this code was found; the description rests on CARB's circuit monitoring requirement and the component information. When the sensor fails, the control module uses a pre-set value and usually runs the supply pump with fixed control.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Often no noticeable change in driving
• Starting problems or hesitation with fixed pump control

Common causes

• High Connector corroded or loose, broken wire
• Medium Sensor faulty
• Medium 5 V reference disturbed (shared with other sensors)
• Low Engine or fuel pump control module, or CAN transmission

Likelihood is a general estimate across vehicles; your make and model may differ.